Number processing in adolescents with prenatal alcohol exposure and ADHD: differences in the neurobehavioral phenotype

Alcohol Clin Exp Res. 2011 Mar;35(3):431-42. doi: 10.1111/j.1530-0277.2010.01360.x. Epub 2010 Dec 16.


Background: Poor arithmetic performance is among the most sensitive outcomes associated with prenatal alcohol exposure and is also common in individuals with attention-deficit hyperactivity disorder (ADHD). We hypothesized that prenatal alcohol exposure would be associated with deficits in the most fundamental aspects of number processing, representation of quantity and distance, whereas ADHD would be associated with deficits in calculation, the form of number processing most dependent on attention and memory.

Methods: Two hundred and sixty-two inner-city, African American adolescents, who had been evaluated prospectively for prenatal alcohol exposure and ADHD, were assessed on a number-processing test comprised of 7 subtests.

Results: More heavily alcohol-exposed adolescents were 4 times more likely to meet diagnostic criteria for ADHD than those whose mothers abstained from alcohol use during pregnancy. Two dimensions of number processing were identified in a factor analysis-magnitude comparison and calculation. As hypothesized, prenatal alcohol exposure was more strongly related to the former and ADHD to the latter. Moreover, the relation of prenatal alcohol to calculation was fully mediated by magnitude comparison, whereas the relation of ADHD to calculation was mediated by IQ but not by magnitude comparison.

Conclusion: These data confirm findings from previous studies identifying arithmetic as a particularly sensitive developmental endpoint for prenatal alcohol exposure. Whereas difficulties with arithmetic in ADHD are mediated by domain-general deficits in overall cognitive ability, fetal alcohol-related arithmetic difficulties are mediated primarily by a specific deficit in the core quantity system involving the ability to mentally represent and manipulate number. These data suggest that different interventions are likely to be effective for remediating arithmetic problems in children with prenatal alcohol exposure than in non-exposed children with ADHD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Alcohol Drinking / adverse effects*
  • Attention Deficit Disorder with Hyperactivity / chemically induced
  • Attention Deficit Disorder with Hyperactivity / diagnosis
  • Attention Deficit Disorder with Hyperactivity / psychology*
  • Cohort Studies
  • Female
  • Humans
  • Learning / drug effects
  • Longitudinal Studies
  • Male
  • Mathematics*
  • Phenotype*
  • Pregnancy
  • Prenatal Exposure Delayed Effects / chemically induced
  • Prenatal Exposure Delayed Effects / diagnosis
  • Prenatal Exposure Delayed Effects / psychology*
  • Prospective Studies